Injectable and biodegradable hydrogels: gelation, biodegradation and biomedical applications

Abstract

Injectable hydrogels with biodegradability have in situ formability which in vitro/in vivo allows an effective and homogeneous encapsulation of drugs/cells, and convenient in vivo surgical operation in a minimally invasive way, causing smaller scar size and less pain for patients. Therefore, they have found a variety of biomedical applications, such as drug delivery, cell encapsulation, and tissue engineering. This critical review systematically summarizes the recent progresses on biodegradable and injectable hydrogels fabricated from natural polymers (chitosan, hyaluronic acid, alginates, gelatin, heparin, chondroitin sulfate, etc.) and biodegradable synthetic polymers (polypeptides, polyesters, polyphosphazenes, etc.). The review includes the novel naturally based hydrogels with high potential for biomedical applications developed in the past five years which integrate the excellent biocompatibility of natural polymers/synthetic polypeptides with structural controllability via chemical modification. The gelation and biodegradation which are two key factors to affect the cell fate or drug delivery are highlighted. A brief outlook on the future of injectable and biodegradable hydrogels is also presented (326 references).

Studies on the Synthesis, Micellization and Gelation of Novel Temperature- and pH-Sensitive ABA Triblock Copolymers

“…(1)100 mL pH 7.4 的缓冲溶液作为释放介质, 将载 药凝胶分别在 25, 37 和 40 ℃下恒温加热, 每隔 10 min 取样 5 mL 测定 BSA 的累积释放量, 同时补充相同的释 放液. (2)载药凝胶在 37 ℃下恒温加热, 100 mL 的 pH 分 别为 1.5, 7.4 和 7.6 的缓冲溶液作为释放介质, 每隔 10 min 取样 5 mL 测定 BSA 的累积释放量, 同时补充相同 的释放液 [31,32] .…”

Evolving Lessons on Nanomaterial-Coated Viral Vectors for Local and Systemic Gene Therapy

“…However, synthetic hydrogels have inherently weak mechanical strength and insufficient biocompatibility that limit their application in biomedicine. Therefore, natural polymer-derived hydrogels have been more extensively studied for various biomedical applications, such as gene, drug and cell delivery [94,[103][104][105][106].…”

Hydrogels for Cardiac Tissue Repair and Regeneration

“…A solution to these problems was represented by synthetic polymers. Synthetic polymers are capable of being tailored to meet specifi c applications because of their properties like porosity, tensile strength, elastic modulus and degradation rate [65][66][67]. For cardiac tissue engineering applications are used some synthetic polymers including poly (ethylene glycol) (PEG), polylactic acid (PLA), poly (lactic-co-glycolic acid) (PLGA), polycaprolactone (PCL), polyurethane (PU), etc [14].…”